1. Field of the Invention.
This invention relates generally to equipment and fittings on boat trailers to facilitate loading and launching of boats. More particularly, the invention relates to a simple accessory device for centering a boat in relation to a trailer while the boat is floating on and supported by the water and which can be extended rearwardly from the trailer by a single handed operation and alongside the boat for loading the boat in alignment with the longitudinal axis of the trailer.
2. Description of the Prior Art.
Many problems are associated with centering a boat with respect to a boat trailer by singlehanded operation particularly under rough and windy conditions. Most prior art arrangements for boat centering rely on structures which cradle or underly the boat or exert pressure on the boat and devices such as those of U.S. Pat. Nos. 3,800,968; 3,896,948; 4,010,962 place reliance on posts or rollers or cradling mechanisms or rocker arms which clamp against the sides of the boat (U.S. Pat. No. 4,033,600) under pressure of hydraulic rams, springs or the like or by reaction of the weight of the boat on levers which transmit this force to side clamping bars. Another type of prior art structure is a gantry (U.S. Pat. No. 4,029,227) wherein the boat is underslung and lowered into and out of the water on the gantry. Other types rely on heavy and complicated retractable auxillary sub-frame or beds or separately wheeled and retractable chassis under-carriages (U.S. Pat. No. 3,984,121). A tilting version of a separate retractable frame is also known (U.S. Pat. No. 3,812,988). Again many of these sliding frames are massive and require hydraulic power for their operation, particularly since they have to bear the additional weight of a loaded boat.
Other problems associated with boat docking and retrieval onto a trailer is that when the trailer is backed down the launching ramp in position under the boat the tail-light assemblies and wheels with bearings and brakes are submerged in water and often in salt water with resultant damage.